Apparatus for controlling the warp tension in a weaving machine

ABSTRACT

THE WEAVING MACHINE HAS A BACK BEAM AROUND WHICH THE WARP IS BENT TO PROVIDE TWO WARP SPAND EXTENDING FROM THE BACK BEAM AT SUBSTANTIALLY A RIGHT ANGLE TO ONE ANOTHER. THE BACK BEAM IS MOUNTED FOR MOVEMENT IN A DIRECTION SUBSTANTIALLY PARALLEL TO ONE OF THE TWO WARP SPAND AND IS URGED IN SUCH DIRECTION BY RESILIENT MEANS TO MAINTAIN THE WARP UNDER PREDETERMINED TENSION. MECHANISM IS PROVIDED TO OPERATE IN RESPONSE TO MOVEMENT OF THE BACK BEAM IN THE OPPOSITE DIRECTION TO FEED THE WARP TOWARD THE BACK BEAM. THE IMPROVEMENT COMPRISES MECHANISM FOR RECIPROCATING THE BACK BEAM IN A PATH SUBSTANTIALLY PARALLEL TO THE OTHER OF THE TWO WARP SPANS, IN SYNCHRONISM WITH THE OPENING AND CLOSING OF THE SHED OF THE WEAVING MACHINE, TO COUNTERACT THE TENDENCY OF THE OPENING AND CLOSING OF THE SHED TO VARY THE TENSION OF THE WARP.

March'Z, 1971 R-AN sEN HAL I 3,567,354

APPARATUS FOR CONTROLLING THE WARP TENSION-IN A WEAVING' MACHINE FiledSept. 19, 1968 v m 3 Sheets-Sheet 1 March .2, T. FRANSSEN ETAL QAPPARATUS FOR CONTROLLING THE WARP TENSIONIN A WEAVING MACHINE FiledSept 19. 1968 Sheets-Sheet 2 March 2, 1971 T FRANSSEN ETAL 3 3,567,354

APPARATUS FOR CONTROLLING THE WARP TENSION INVA WEAVING MACHINE FiledSept. 19, 1968 3 Sheets-Sheet s United States Patent 5 Int. Cl. D03c49/06 US. Cl. 139-408 2 Claims ABSTRACT OF THE DISCLOSURE The weavingmachine has a back beam around which the warp is bent to provide twowarp spans extending from the back beam at substantially a right angleto one another. The back beam is mounted for movement in a directionsubstantially parallel to one of the two warp spans and is urged in suchdirection by resilient means to maintain the warp under predeterminedtension. Mechanism is provided to operate in response to movement of theback beam in the opposite direction to feed the warp toward the backbeam. The improvement comprises mechanism for reciprocating the backbeam in a path substantially parallel to the other of the two warpspans, in synchronism with the opening and closing of the shed of theWeaving machine, to counteract the tendency of the opening and closingof the shed to vary the tension of the warp.

BACKGROUND OF THE INVENTION The invention relates to a weaving machineprovided with a movably supported back beam coopearting with anadjustable driving mechanism for the warp beam by means of a leversystem as known per se in modern weaving machines.

In this known weaving machine the back beam is reciprocable over a shortdistance in order to prevent an increasing of the tension in the warpwhen the shed is entirely opened by the shaft. In such looms themovement of the back beam is used for controlling a driving mecha nismfor the warp beam in order to keep the tension in the warp as constantas possible when the warp is unrolled from the warp beam. In thisweaving machine use is made of a friction coupling in the drivingmechanism which friction coupling is controlled by the lever system ofthe back beam which can be displaced against the action of a spring. Theprovision of a spring device as intermediate element for controlling thedriving mechanism of the warp beam operates smoothly, however it ispossible that the driving of the warp beam may be inaccurate and tooslow when the weaving speed of the weaving machine is increased.

SUMMARY OF THE INVENTION The object of the invention is to improve sucha weaving machine so that a very exact regulation of the unrolling ofthe warp from the warp beam is possible whereas the back beam will makeits normal reciprocal movement for compensating the warp tension as aresult of the opening and closing of the shed.

According to the invention this is attained in a weaving loom which ischaracterized in that a contact arm which makes contact with thecircumferential surface of the warp beam as known per se cooperates witha continuously variable speed driving mechanism for the warp beam whichhas been adapted in such a manner that the warp beam is driven with asurplus of speed whereas the coupling which can be controlled by thelever system of the back beam as known per se has been inserted betweenthe 3,567,354 Patented Mar. 2, 1971 ice" driving mechanism and the warpbeam and in which the lever system together with the coupling has beenadapted as a stop for the back beam in one end position. The couplingthus interrupts the driving of the warp beam and as a result of theabsence of the spring mechanism the coupling can be immediatelydisconnected at the desired moment and as the back beam periodicallymakes an oscillating movement as a result of its driving synchronouslywith the opening and closing of the shed the coupling will makesuccessive short strokes in which depending on the average tension inthe warp the coupling connects the driving shaft with the driven shaftof the driving mechanism for the warp beam during a small period of itsstroke. As a result of the adjustment in the surplus of the drivingspeed and by the adjustment of the correct stroke of the coupling withits concerning lever system for driving of the warp beam for unwindingthe warp, an exact regulation is obtained.

It is to be remarked that the provision of a continuously variable speeddriving mechanism for the warp beam is already known. Such a mechanismin the shape of a V-belt gear is controlled immediately by movement ofthe back beam owing to which the regulation of the unwinding of the warpis not exact and slow.

The practical embodiment of a weaving machine in which the back beam hasbeen movably supported according the invention is characterized in thatthe back beam has been supported in bearings which can move in thelongitudinal direction of rocker arms, which bearings are supported onpushing rods which can make a reciprocable axial movement depending onthe movement of the reed, whereas the rocker arms rest against a leverby the tension of the warp which lever forms a part of the lever systemof the coupling in the driving mechanism. One special object of theinvention is to adapt the driving mechanism for the warp beam in theloom in such a manner that the coupling which cooperates with the leversystem is double acting in which a part of the coupling cooperating withthe driving shaft has been adapted as a friction coupling and the partcooperating with the driven shaft has been adapted as a claw coupling.The claws of the coupling which cooperates with the lever system intermesh with the claws of the part of the coupling mounted on the drivenshaft when the weaving machine is in normal operation, whereas the partof the coupling cooperating with the lever system has been mounted insuch a manner that it can freely rotate around the driving shaft and canengage with its friction surface against a friction surface which hasbeen fastened to the driving shaft.

By the provision of such a double acting claw coupling it is possible toreverse the driving of the warp beam, e.g. when the weaving machine isto be set back in order to be able to correct a weaving defect.

An approximate regulation of the driving of the warp is possible becausethe driving shaft is provided with a continuously variable speed drivein which the adjusting part has been connected to a contact arm whichrests on the circumferential surface of the warp beam owing to whichwhen the diameter of the warp beam decreases a higher rate of speed canbe given to the driving shaft.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram in which thedriving mechanisms for the warp beam, a back beam, a chest beam and acloth beam have been indicated together with two lever systems whichcooperate with the back beam;

FIG. 2 is a side view partly in section of a part of the drivingmechanism for the warp beam showing a part of the lever systemcooperating with the coupling and FIG. 3 shows a further side view,partly in section of the driving mechanism for the warp beam near thestep- 3 less regulator cooperating with the arm resting on thecircumference of the warp beam.

Some main parts of the weaving machine are shown in the diagram of FIG.1 in which the warp beam 1 together with the Warp 2 rigged thereon, theback beam 3, the Weaving shafts A, the reed B, the chest beam C, thesand beam D and the cloth beam B have been indicated.

The warp beam is driven by means of a separate driving mechanism in sucha manner that independently of the diameter of the warp beam 1 thetension in the warp 2 remains always the same. The back beam 3 has beenmovably supported in gaps 4 in rocker arms 6 which are pivoted at 5. Thebearings of the back beam in the gaps 4 rest on the ends of pushing rods8 which at their lower ends are supported on lever 10 pivotablysupported at 9. By means of couplings 11, 12, 13 and bell crank levers14 and 15 the lever 10 has been connected to an arm 17 of the rotatableshaft 16 of the reed. When the reed B rocks around its shaft 16 the arm17 makes also a rocking movement owing to which the pushing rods 8 aresubjected to a reciprocal axial movement in a path substantiallyparallel to the warp span which extends between the warp beam 1 and theback beam 3 and is substantially at a right angle to the warp span whichextends from the back beam 3 to the chest beam C. When the reed B has aretracted position, thus a position in which the shed as a result of themovement of the weaving shafts A is entirely open the pushing rods willtake their lowermost position, that is to say a position in which theback beam 3 has its nearest position to the pivot point 5 of the rockerarms 6. By this displacement of the back beam in the gaps 4 the warpthreads 2 are somewhat released in such an amount as the increasing oftension in the warp as a result of the opening of the shed, tocounteract the tendency of the' opening and closing of the shed to varythe tension of the warp. As the gaps 4 run parallel to the longitudinaldirection of the rocker arms 6 the movement of the back beam 3 by theaction of the pushing rods 8 will not have any component in the rockingdirection of the arms 6 that is to say no inconvenient side effects inthe rocking movement of the arms 6 are caused because the bearings ofthe back beam 3 are mounted in the gaps 4 for sliding movement in adirection substantially radial to the axis 5 about which the supportingrocker arms 6 are pivoted. The position of the rocker arms 6 dependsonly on the sum of the tensions in the warpthreads 2. As a result of thetension in the warp the rocker arms 6 rest against the free end of alever 19 which has been pivotally supported at 18. The lever 19 isfurther connected to a lever 21 by means of a link 20. The lever 21 hasbeen pivotally supported at 22. Further the lever 21 has been connectedto a bell crank lever 25 by means of a link 23. The lever 25 has beenpivotally supported at 24 and cooperates with a movable part 26 of thecoupling which is a part of the driving mechanism for the warp beam.

A spring has been connected to the free end of the lever 21 and thespring action can be adjusted in order to keep the entire lever systembetween the rocker arms 6 and the coupling 26 under proper tension andto urge the back beam in a direction substantially parallel to the warpspan that extends from the back beam 3 to the chest beam C so as tomaintain the warp under predetermined tension. When now the tension inthe warp 2 increases the back beam 3 will be moved in a directionopposite to that which the back beam is urged by the spring actingthrough the levers 21 and 19, as the rocker arms 6 will swing around thepivot 5 and the rocker arms 6 will displace the lever 19 owing to whichthe coupling 26 will be engaged to feed the warp toward the back beam.That is to say the friction surface of the coupling 26 comes intocontact against the friction surface 28 of the driving shaft 29 and therotation of the shaft 29 will be transferred to the driven shaft 42 ofthe driving mechanism and the beam 1 will be driven as a result of theconnection of the coupling 26*. When the warp beam 1 is driven thetension in the warp 4 2 will immediately decrease and the back beamtogether with the rocker arms 6 will return as a result of the action ofthe spring of the lever 21. Thus the lever 19 pushes the rocker arms 6back. If desired the action on the rocker arms 6 can be supportedby anauxiliary spring.

As the amount of driving the warp beam 1 must be less when the beam isfully loaded than when the beam is nearly empty the operation of thecoupling 26 would be more frequent when the warp beam 1 is moreunrolled. In order to obtain a good unrolling of the warp the periodduring which the coupling 26 is engaged when the warp beam is partlyunrolled would have to be larger than with an entirely loaded beam. Thiscould be disadvantageous because extremes in tensions of the warp couldarise. In order to avoid this drawback the driving shaft 29 will havedifferent speeds of rotation depending on the diameter of the warp beam.For this purpose a contact arm 31 known per se has been provided. Theoperation of such a contact arm in varying the driving speed of thedriving shaft 29 will be described later.

The coupling 26 which has been diagrammatically indicated in FIG. 1 hasbeen shown in FIG. 2 together with the friction surface 28, the drivingshaft 29, the driven shaft 42 and the lever 25 for actuating thecoupling 26. The coupling 26 has a central part that fits slidablyaround the shaft 29. If desired an especial side bearing can beprovided. Further the coupling 26 can freely rotate around the shaft 29.A pressure spring 32 has been situated around the shaft 29 between thecoupling 26 and the friction surface 28 which has the shape of a disc.The friction surface 28 has a tight fit around the driving shaft 29 andis prevented from rotation by means of a key 33. A circumferentialgroove 37 has been formed by means of a circumferential flange 34 and anendplate 35 which has been connected to the coupling part 26 by means ofscrews. A pin 38 of the lever 25 projects into the circumferentialgroove 37. The side of the endplate 35 which is remote from the groove37 has been provided with a crown of teeth 39 which forms the claws of aclaw coupling. The teeth 39 cooperate with a similar crown of teeth atan end surface of a claw coupling 41 provided with a circumferentialgroove 46. The claw coupling 41 is prevented from rotating however, itcan move in an axial direction on the driven shaft 42 of the drivingmechanism. In order to prevent the coupling 41 for rotating around theshaft 42 a key 43 has been mounted on the shaft 42. By means of pin 44of a lever 46 which can rock around the shaft 45 and which pin projectsinto a circumferential groove 40 of the coupling 41 this coupling can becaused to contact the crown of teeth 39 of the coupling 26. The coupling41 has been adapted as a stop for the coupling 26. The lever 46 has beenconnected to a pushing rod 47 whose length can be adjusted by means of aturnbuckle 48. The pushing rod 47 has been connected to a control deviceeg an electromagnet which can be energized in such a manner that thecoupling 41 intermeshes with the crown of teeth 39 or will be entirelyfree from the teeth. When the coupling 41, which is double acting, isfree from the teeth 39 of the coupling 26 the teeth 50 of the coupling41 intermesh with with the teeth 51 of a gear Wheel 52 which can freelyrotate around the shaft 42. The gear wheel 52 however, cannot move in anaxial direction. Further the driven shaft 42 has been coupled with agear box 53 which has been adapted as a reduction gear. A pinion (notshown) of the gear box 53 intermeshes with a gear wheel which isconnected to the warp beam in a known manner. This gear wheel has beendiagrammatically shown with a dash dotted line 54.

When the coupling 41 has been released from the coupling 26 the drivingshaft 29 has been disconnected from the driven shaft 42 also when thefriction surface 55 of the coupling 26 rests against the frictionsurface 23. As has been stated above in this condition the teeth 50 ofthe coupling 41 intermesh with the teeth 51 of the gear wheel 52. Thisis possible when the electromagnet 49 has been energized. The teeth ofthe gear wheel 52 intermesh with the teeth of a pinion 56 mounted on theshaft of an electric motor 57.

When the electric motor 57 is energized the gear wheel 52 will be drivenand the rotation is transferred to the driven shaft 42 via the coupling41. The direction of the motor 57 is such that the shaft 42 is driven ina direction opposed to the direction of rotation of the shaft 29. Underthese circumstances the direction of rotation of the warp beam isreversed and the warp will be wound up. This facilitates the correctionof weaving defects when some wefts are to be removed. Up to now the warpbeam has to be reversed by hand and this so called back weaving can beregulated from the operation panel of the weaving machine.

As has been stated above the speed of the driving shaft 29 can beregulated by means of a contact arm 31 which rests against thecircumference of the warp beam.

In order to perform such a regulation the shaft 29 has been providedwith a gear wheel 58 which intermeshes with a long pinion 59. Thispinion 59 has been mounted on a shaft of a contact wheel 60 which restsagainst the end surface of a friction disc 61. The friction disc 61 isdriven by a rotating part of the weaving machine e.g. by the main shaft62 of the weaving machine and a chain 63 as indicated by a dash dottedline in FIG. 3.

The contact wheel has been mounted in ears 64 and 65 of a bushing 66which can pivot and move in an axial direction around the driving shaft29. The ears 64 and 65 have been positioned in such a manner withrespect to the bushing 66 that the contact wheel presses against thefriction disc 61 as a result of the reaction between the teeth of thepinion 59 and the gear wheel 58. The bushing 66 has been provided with atooth rack 67 which intermeshes with a tooth sector 68.

The tooth sector 68 has been mounted on a rotatably supported shaft 69which has been further provided with a tooth sector 70. The tooth sector70 meshes into a tooth rack of a driving rod 71 which engages by meansof a pin 72 in a guiding slot situated in a plate 75 of the contact arm31. For clearness sake the circumference of the warp beam has beenindicated by a dash dotted line 76. The roller 78 of the contact arm 31makes immediate contact with the packet of warp threads on the warp.When now the warp threads are to be drawn from the warp beam thecircumference of the warp beam will be decreased and the contact arm 31will follow and rotate around its shaft 79. The guiding slot possesses apart 73a which has been concentrically situated around the shaft 79.This part of the slot has been provided in order to be able to lift thecontact arm 31 from the entirely loaded beam without moving the contactwheel 60 in a radial direction on the friction disc 61 as a result ofmoving of the contact arm 31. Lifting the contact arm 31 facilitatesplacing of a new warp beam. The part 7312 of the guiding slot isapproximately straight and is used when the contact arm 31 follows thedecreasing diameter of the warp beam as a result of which the contactarm 31 will be displaced. As a result of such displacement the bushing66 moves in an axial direction with respect to the driving shaft 29 andthe contact wheel will be displaced on the friction disc 61. By thelarge rate of transmission between the pinion 59 on the shaft of thecontact wheel 60 and the gear wheel 58 only slight pressure of thecontact wheel 60 against the friction disc 61 is sufficient for a gooddriving of the warp beam. When the contact wheel 60 moves outwardly in aradial direction on the friction disc 61 the driving shaft 29 willobtain a higher rotation speed. The rotation is only transmitted to thedriven shaft 42 when the friction surface 55 of the coupling 26 pressesagainst the friction surface 28 and the teeth of the coupling 41intermesh with the teeth 39 of the coupling 26. As the operation of thecoupling 26 as a result of the position of the back beam 3 with itsrocker arm 6 is intermittently performed it is desired that the drivingshaft 29 have an excess of speed. The coupling 26 cooperates also with astationary friction surface 28a, owing to which the coupling 26 will bestopped when it is released from the friction surface 28.

A contact wheel 60 and a friction disc 61 have been described as anexample of a continuously variable speed driving mechanism. Anotherdriving mechanism e.g. the driving mechanism shown in FIG. 1 can be usedalso. This driving mechanism which can be considered as a unit has beenprovided with an operation lever and a pushing rod 71 connected to thecontact arm 31. The pushing rod 71 and the operating lever 70 in FIG. 1can be considered as the same parts as the sliding rod 71 and the sector70 in FIG. 3, as they are just elements for transferring the movement ofthe arm 31 to the contact transmission.

We claim:

1. Apparatus for controlling the warp tension in a weaving machinehaving a back beam around which the warp is bent to provide two Warpspans extending from the back beam at substantially a right angle to oneanother, the back beam being mounted for movement in a pathsubstantially parallel to one of the two warp spans, comprisingresilient means for urging the back beam in such path, in a direction tomaintain the warp under tension, and mechanism which operates, inresponse to movement of the back beam in the opposite direction, to feedthe warp toward the back beam, wherein the improvement comprises drivingmechanism for reciprocating the back beam in a path substantiallyparallel to the other of the two warp spans, in synchronism with theopening and closing of the shed of the weaving machine, to counteractthe tendency of the opening and closing of the shed to vary the tensionof the warp.

2. Apparatus according to claim 1 wherein the back beam is rotatablysupported in bearings that are mounted, in a support which is pivotableabout a fixed axis, for sliding movement in a direction substantiallyradial to such axis, and the reciprocating mechanism is connected toreciprocate the bearings in their slidable mounting.

References Cited UNITED STATES PATENTS 1,667,221 4/1928 Sakamoto 139l082,609,006 9/1952 Lord 139108 2,812,780 11/1957 Sakamoto 1391082,819,734- l/1958 Pfarrwaller 1391 10 2,914,092 ll/ 1959 Clentimack139108 3,125,128 3/1964 Pfarrwaller 1391 15 FOREIGN PATENTS 861,3452/1961 Great Britain 139-108 JAMES KEE CHI, Primary Examiner

